JPH01302291A - Control system for supply current to display - Google Patents

Abstract

PURPOSE:To easily detect a change of display by supplying a driving current to the display for a constant time only when display data is changed. CONSTITUTION:When the display data is inputted from an external device or keyboard 10, it is inputted to a memory 131 or 132 of a memory part 13 and its image is displayed for a certain time. Then when new display data is inputted thereafter, it is inputted to the memory 132 or 131. A central processor 4 compares the display data which is supplied currently to a CRT 7 with data inputted to the memory part 13 newly every time the display data is inputted newly and turns on a changeover switch 14 when detecting any difference to output it from a display control circuit 6 to the CRT 7 through a character generation part 5. Consequently, only when the display data is changed, the driving current is supplied to the display for the certain time to make the change of the display easy to detect.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling current supplied to a display provided in a terminal device.

[Conventional technology]

FIG. 3 is a block diagram showing the configuration of a conventional terminal device.

The terminal device of this conventional example includes a main body 1, a keyboard 10, and a power supply 12. Inside the main body 1, there are an interface section 2, a memory 3, a central processing unit 4, a character generation section 5, a display control circuit 6, and a CRT 7 serving as a display.
, a clock 8, and a power supply section 9 are provided. Each circuit (interface section 2, memory 3, central processing unit 4, character generation section 5, display control circuit 6) inside the main body 1 operates according to a clock signal supplied from the clock 8. The interface unit 2 is connected to a keyboard 10, an external device (not shown), a memory 3, and a central processing unit 4,
Signals are sent and received between the main body 1 and other devices. The central processing unit 4 is also connected to a memory 3 and a character generation unit 5, and controls the operation of the terminal device. The display control circuit 6 receives the output from the character generator 5 and causes the CRT 7 to display the content indicated by the output. Power supply section 9 is C
A power supply provided for the RT 7 and connected to the power supply 12 via a switch 11.

Screen display on the CRT 7 is performed by the following procedure.

Image data input from the keyboard 10 or an external device is taken into the memory 3 via the interface section 2. When the central processing unit v14 detects that image data has been input, it reads out the contents of the memory 3 and sends it to the character generation section 5. The character generation section 5 generates a character pattern indicated by the input image data and outputs it to the display circuit 6.
Display it on the CRT7 screen.

In this terminal device, the control of the current supplied to the CRT 7 is as follows:
This is done by the terminal user opening and closing the switch 11.

(Problems to be Solved by the Invention) The control of the current supplied to the display in the conventional terminal device described above is performed by the terminal user.Therefore, continuous operation is performed for a long time, and abnormalities may occur. If the terminal device is built into a system that notifies the terminal user by displaying a message to that effect on the display when an event occurs, the terminal user must keep the display running at all times to keep an eye on changes in the screen. Yes.For this reason,
Since the display is constantly displaying information, there is a risk of not noticing changes in the display and overlooking the occurrence of abnormalities. However, it has the disadvantage that resolution and brightness deteriorate due to ion burnout that occurs over time.

[Means to solve the problem]

The current supply method to the display of the present invention stores the first display data currently being supplied to the display and the second display data newly inputted following the first display data. and a switching means for stopping/starting current supply to the display; and comparing the contents of the first and second display data stored in the storage means, and if the contents are the same; The control means causes the switching means to stop supplying current to the display, and when the contents are different, causes the switching means to continue supplying current to the display for a certain period of time.

[Effect]

Current is supplied to the display only when a change occurs in the displayed data. Therefore, the terminal device user can easily know that the display has changed.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a terminal device that implements the supply current control method to a display according to the present invention, and FIG.
It is a flowchart which shows the control a operation|movement of the switch 14 in a figure.

In this embodiment, a changeover switch 14 that operates under the control of the central processing unit 4 and has the function of stopping and restarting the current is provided between the CR 177 of the conventional example shown in FIG.
The memory 3 is a memory section 13 consisting of memories 131 and 132.
That is.

Components with the same functions as conventional ones are given the same numbers.

The memories 131 and 132 alternately store display data currently being supplied to the CRT 7 and newly input display data.

Next, the operation of this embodiment will be explained with reference to FIG.

When the operation is started, first, an image is displayed based on display data input from an external device or the keyboard 10 and stored in one of the memories 131 and 132 (for example, 131) (step 21). Thereafter, when new display data is input from an external device or the keyboard 10, it is captured and stored in the memory 132. In step 2, the central processing unit 4 detects new input of display data.
2) The display data stored in the memory 131 and currently being supplied to the CRT 7 is compared with the newly input display data stored in the memory 132.Step 23) The presence or absence of a difference is detected. (Step 24).

As a result, if a difference is detected, the newly inputted display data is continuously outputted from the memory 132, converted into a character pattern by the character generation section 5, and then the display control circuit 6
output to the CRT7. In addition, for the changeover switch 14, it is checked whether the circuit is closed (step 28), and if it is not closed, a signal is output to close the changeover switch 14 (step 2).
is closed (step 30), and current is supplied to CR-r7. If no new input is detected or if no difference is detected as a result of comparing the data stored in the memories 131 and 132, check whether a certain period of time has passed since the display started (step 25); If the elapsed time has not elapsed, the changeover switch 14 is closed by the above-described operation. Further, if a certain period of time has elapsed, output a signal to circuit the selector switch 14 (step 26).
, open the selector switch 14 (step 27), and
The supply current to T7 is stopped.

With the above configuration, in the terminal device of this embodiment, if no difference is detected in the stored contents of the memories 131 and 132, the current supply to the CRT 7 is stopped.
If a difference is detected, current is supplied to the CRT 7 for the above-mentioned predetermined period of time.

〔Effect of the invention〕

As explained above, the present invention supplies drive current to the display for a certain period of time only when there is a change in display data, so that the display operates only when there is a change in the display screen. Become. For this reason,
This has the effect of making it easier for the terminal device user to detect changes in the display, and also reduces the display time of the display, thereby extending the life of the display.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a terminal device according to the present invention, FIG. 2 is a flowchart showing its control operation, and FIG. 3 is a block diagram showing the configuration of a conventional terminal device. DESCRIPTION OF SYMBOLS 1...Main body, 2...Interface section, 4...Central processing unit, 5...Character generation section, 6
...Display control circuit, 7...CRT. 8...Clock, 9...Power supply section, 10.
...keyboard, 11...switch, 12...
Power supply, 13...Memory section, 13+, 1
32...Memory, 14...Selector switch. Patent applicant: NEC Corporation Representative: Patent attorney: Han Uchihara Figure 2

Claims (1)

[Scope of Claims] A system for controlling supply current to a display provided in a terminal device, comprising: first display data currently being supplied to the display; a storage means for storing newly input second display data; a switching means for stopping/starting the current supply to the display; and a storage means for storing the second display data newly inputted; When the contents of the display data are the same, the switching means stops supplying current to the display, and when the contents are different, the switching means stops supplying current to the display. A control method for controlling the supply of current to a display, comprising a control means for supplying current for a certain period of time.